A fluid working system such as a pump for displacing a working fluid such as hydraulic fluid or a motor using a working fluid is provided. The system may have a positive displacement machine which includes one or more working chamber with displacement means such as a cylinder with a reciprocating piston. There are also two or more fluid ports to allow the working fluid to flow into and out of the working chamber. The working fluid flows from one fluid port means to another either being forced to do so when pumped or moving the piston when functioning as an engine. The fluid working system has associated therewith a non-dead compliance volume of a material such as syntactic foam. This compliance volume acts to smooth any pressure fluctuations within the working fluid system.

A screw compressor having screw rotors for compressing a process gas, a pipe bend conducting compressed process gas towards a silencer. The pipe bend at an inlet-side portion comprises a first connecting piece fastening the pipe bend to a pressure port and on an outlet-side portion a second connecting piece for fastening the pipe bend to the silencer. The pipe bend has a flow channel between the connecting pieces defined by an inner wall and an insert that projects into the inlet-side portion of the pipe bend. An outer wall of the insert projecting into the flow channel of the pipe bend and a portion of the inner wall of the pipe bend enclosing this outer wall on the outside delimit a space acting as resonator, coupled to the flow channel of the pipe bend.

Disclosed are a sliding vane compressor and an exhaust structure thereof. The exhaust structure of the sliding vane compressor includes: an exhaust hole, the exhaust hole being formed in a flange of the sliding vane compressor and being in communication with a compression cavity of a cylinder of the sliding vane compressor; a guide channel, the guide channel being formed on the flange and penetrating through the flange; and an exhaust channel, the exhaust channel being formed on an eccentric circle of the sliding vane compressor, and the exhaust channel being used for communicating the compression cavity with the guide channel using the rotation of the eccentric circle. The sliding vane compressor and the exhaust structure thereof have a small exhaust loss, thereby effectively reducing the power consumption and the production and manufacturing costs of the sliding vane compressor.

In a gear pump, a gear chamber is defined in a housing hole of a housing. A pair of gears is housed in the gear chamber. The gears are rotatably supported at support holes of a pair of side plates via support shafts. As viewed in an axial direction of the support shafts during rotation of the gears, addendum circles of the gears displaced under a differential pressure between a low-pressure chamber and a high-pressure chamber form first contact points with respect to an inner peripheral surface that defines a housing hole. As viewed in the axial direction of the support shafts during rotation of the gears, the first contact points are covered with the side plates displaced under the differential pressure.

An object of the present invention is to provide a variable displacement vane pump capable of further reducing a pulse pressure. A vane pump (1) includes a cam ring (33). The cam ring (33) is annularly formed, and defines a plurality of pump chambers (38) on an inner peripheral side thereof in cooperation with a rotor (31) and vanes (32). An inner peripheral surface (330) of the cam ring (33) is formed in such a manner that, assuming that a confinement region refers to a region between an end portion of an intake port (221) and an end portion of a discharge port (222), at a timing when the pump chamber (38) communicates with or is disconnected from the discharge port (222) on one side corresponding to one of confinement regions or a timing close thereto, a change in a volume change amount of the pump chamber (38) on another side corresponding to the other of the confinement regions has an extreme value in a direction for reducing a change in a discharge amount at the time of the above-described communication/disconnection.

A vane pump includes a casing, a rotor, vanes, a motor, and a fixed member. The casing defines a pump chamber therein. The rotor is disposed in the casing and configured to eccentrically rotate relative to the casing. The vanes are configured to rotate together with the rotor to slidably move on an inner surface of the casing. The motor is configured to rotate the rotor. Both the motor and the casing are fixed to the fixed member. The casing has an outer side wall surface and a flange. The flange protrudes outward from the outer side wall surface at an intermediate position between both ends of the pump chamber in a rotational axis direction of the rotor. The flange is fixed to the fixed member at a plurality of positions. The fixed member has a linear expansion coefficient that is different from that of the casing.

The present invention provides a fluid transfer apparatus comprising: a rotating shaft comprising a rotation unit extending along an axial direction and a first eccentric unit and a second eccentric unit disposed to be spaced apart from each other along the axial direction; a first rotor housing forming a first fluid compression space in the shape of an epitrochoid curved surface; a second rotor housing forming a second fluid compression space in the shape of an epitrochoid curved surface, and positioned to be spaced apart from the first rotor housing along the axial direction; a first rotor disposed in the first fluid compression space so as to delimit the first fluid compression space into multiple variable-displacement spaces, and coupled to the first eccentric unit while surrounding the first eccentric unit in the radial direction of the first eccentric unit; and a second rotor disposed in the second fluid compression space so as to delimit the second fluid compression space into multiple variable-displacement spaces, and coupled to the second eccentric unit while surrounding the second eccentric unit in the radial direction of the second eccentric unit.

A rotary pump, preferably a vane cell pump or a pendulum slider pump, includes a stator and a rotor which rotates about a rotational axis within the stator. The rotor includes multiple delivery elements which move radially in relation to the rotational axis, and two adjacent delivery elements limit a delivery cell together with the outer surface area of the rotor and the inner surface area of the stator. At least two delivery cells, preferably two adjacent delivery cells, exhibiting a first maximum cell volume form a first delivery cell group and at least two other delivery cells, preferably two other adjacent delivery cells, exhibiting a second maximum cell volume form a second delivery cell group. The first maximum cell volume of the delivery cells of the first delivery cell group is larger than the second maximum cell volume of the delivery cells of the second delivery cell group.

A screw-spindle pump includes: a first (drive) screw spindle and a second (running) screw spindle that runs oppositely with respect to the first screw spindle; and a pump housing configured to receive the first and second screw spindles. The first and second screw spindles form, together with at least the pump housing, delivery chambers, which move from a suction side of the pump to a pressure side of the pump due to a rotation of the first and second screw spindles. The pump housing has a first abutment insert for the first screw spindle and a second abutment insert for the second screw spindle, and at least one of the first and second abutment inserts is set angled with respect to a first plane of the pump, to counteract operationally induced crossing of the first and second screw spindles.

An electric pump actuator for a continuously variable transmission includes a gear wheel pump, a first electric motor, a second electric motor, and an electric control unit. The gear wheel pump has a first gear wheel and a second gear wheel meshing with the first gear wheel. The first electric motor is for actuating the first gear wheel, and the second electric motor is for actuating the second gear wheel independent of the first gear wheel. The electronic control unit is arranged to control the first electric motor to transmit a first torque to the first gear wheel, and control the second electric motor to transmit a second torque to the second gear wheel that is set against the first torque in at least one rotation angle range.